Coil

Coil usually refers to the annular wire winding, the most common applications are: motor, inductance coil, transformer and an annular antenna.

In the winding circuit refers to the inductor. Is the guide line of a winding up, wire insulation each other, while the insulating tube can be hollow, can also contain iron core or a magnetic core, referred to as inductance. Inductance can be divided into fixed and variable inductance inductance inductance coil is fixed, a wire ring by ring to the insulation around the pipe, wire insulation each other, while the insulating tube can be hollow, can also contain iron core or a magnetic core, referred to as the inductance and coil. To express with L, Henry ( H ) unit, don Henry ( mH ), Henry chinkapin ( uH ), 1H = 10 ^ 3mH = 10 ^ 6uH.

One, the inductance of the classification

According to the inductive classification: fixed inductance, variable inductance.

According to the magnetic properties of classification: air core coil, ferrite coil, core coil, copper core coil.

According to the working character of classification: antenna coil, the oscillating coil, choke coil, trap coil, deflection coil.

According to the winding structure classification: monolayer, multilayer coil coil, honeycomb coil.

In two, the main characteristic parameters of inductance coil

In 1, the inductance L

Inductance L said coil itself inherent characteristic, and current size. In addition to the special ( color code inductance inductance coil and inductance ), generally not specially marked on the coil, while the specific name tagging.

2, inductance XL

Inductance coil of the alternating current block size called the inductance XL, in ohms. It and the inductance L and AC frequency between F XL = 2 pi fL

3, the quality factor Q

The quality factor Q is said coil quality of a physical quantity, Q inductance XL and equivalent resistance ratio, namely: Q = XL / R.

Coil Q value more, smaller loop loss. Coil Q and conductor DC resistance, skeleton of the dielectric loss, the shield or core loss caused by the skin effect, frequency effect and other factors. Coil Q values are usually tens to hundreds of.

In 4, the distributed capacitance

The coil and the coil turns, and the shielding cover, and the bottom plate between the coil between the capacitance is called distributed capacitance. Distributed capacitance exists so that the coil Q value decreased, bad stability, so the distributed capacitance of the coil as small as possible.

Three, common coil

1, single-layer coils

Single layer coil is insulated wire ring by a enclosure around the tube or bakelite skeleton. Such as the transistor radio antenna coil.

2, honeycomb coil

If the winding coil, the plane is not parallel with rotating surface, but intersect to form a certain angle, the coil is called honeycomb coil. While its rotation, and the number of wire bent, often referred to as the break point. Honeycomb winding method has the advantages of small volume, small distributed capacitance, and inductance quantity. Honeycomb coil is the use of honeycomb winding machine for coiling, folding point more smaller, distributed capacitance

In 3, a ferrite core and iron core coil

The inductance of the coil size and have no core on. In the air core coil is inserted in a ferrite core, can increase the inductance coil and improve quality factor.

In 4, copper core coil

Copper core coil in the VHF range widely, using the copper core in the coil position to change the inductance, the adjustment is convenient, durable.

5, color code inductor

Color code inductor with fixed inductance inductor, its inductance mark method with resistance to color ring to mark.

6, chokes ( choke )

Alternating current through the coil is called restriction chokes, divided frequency choke coil and low frequency choke coil.

7, deflection coil

Deflection coil is a television scanning circuit output stage load, deflection coil requirements: high deflection sensitivity, the uniformity of the magnetic field, high Q value, small volume, low price.

Knitted fabric of the basic component unit, a space curve shape. Two ring column, a needle loop and a settlement arc ( or extension line ).